高产奶牛通常会经历强烈的细胞代谢,导致乳腺组织的氧化应激。我们的研究发现,这些高产奶牛的过氧化氢(H2O2)水平显着升高,脂过氧化物酶,和他们血液中的总抗氧化能力,与普通奶牛相比。这种增加的氧化应激与基因如GCLC的表达增加有关。高产奶牛乳腺组织中的GCLM和SIRT1以及SIRT1等蛋白质。用H2O2刺激MAC-T细胞,其浓度等于道德高产奶牛血清中的平均H2O2水平,由测定试剂盒检测。我们的观察结果表明,短期暴露于H2O2(12小时)会上调SIRT1基因和蛋白质的表达。它还增加了SOD2,CAT,GCLC,GCLM,PGC-1α,和NQO1,提高了AMPK的磷酸化,PGC-1α蛋白表达增强,NQO1、Nrf2和HO-1,同时降低NF-κB的磷酸化。此外,短期H2O2刺激导致总抗氧化能力增加,SOD,GSH,奶牛乳腺上皮细胞中的CAT水平。相比之下,长时间暴露于H2O2(24小时)产生相反的结果,表明抗氧化能力降低。进一步的研究表明,SIRT1抑制剂(EX527)可以逆转由短期氧化应激引发的细胞抗氧化能力的增强。然而,重要的是要注意,虽然12小时H2O2刺激提高了抗氧化能力,细胞内活性氧(ROS)和丙二醛(MDA)水平随时间逐渐升高,表明长期刺激下的损伤更大。相反,SIRT1激活剂(SRT2104)可以逆转长期氧化应激导致的细胞抗氧化能力降低,显著抑制ROS和MDA的积累。值得注意的是,SRT2104在哺乳期间在MAC-T细胞中表现出类似的作用。总之,SIRT1对奶牛乳腺上皮细胞的抗氧化能力具有重要的调节作用。这一发现为乳腺细胞的抗氧化机制提供了有价值的见解,这可以作为未来乳腺健康策略的理论基础。
High-yield dairy cows typically undergo intense cellular metabolism, leading to oxidative stress in their mammary tissues. Our study found that these high-yield cows had significantly elevated levels of hydrogen peroxide (H2O2), lipoperoxidase, and total antioxidant capacity in their blood, compared with ordinary cows. This increased oxidative stress is associated with heightened expression of genes such as GCLC, GCLM and
SIRT1 and proteins such as
SIRT1 in the mammary tissue of high-yield cows. MAC-T cells were stimulated with H2O2 at a concentration equal to the average H2O2 level in the serum of ethically high-yielding cows, as detected by an assay kit. Our observations revealed that short-term exposure (12 h) to H2O2 upregulated the expression of
SIRT1 gene and protein. It also increased gene expression for SOD2, CAT, GCLC, GCLM, PGC-1α, and NQO1, elevated the phosphorylation of AMPK, and enhanced protein expression of PGC-1α, NQO1, Nrf2, and HO-1, while reducing the phosphorylation of NF-κB. Additionally, short-term H2O2 stimulation resulted in increased total antioxidant capacity, SOD, GSH, and CAT levels in the mammary epithelial cells of dairy cows. In contrast, prolonged exposure to H2O2 (24 h) yielded opposite results, indicating reduced antioxidant capacity. Further investigation showed that
SIRT1 inhibitor (EX 527) could reverse the enhanced cellular antioxidant capacity triggered by short-term oxidative stress. However, it is crucial to note that while 12 h H2O2 stimulation improved antioxidant capacity, reactive oxygen species (ROS) and malondialdehyde (MDA) levels inside the cell gradually increased over time, suggesting greater damage under long-term stimulation. Conversely, the
SIRT1 activator (SRT 2104) could reverse the reduced cellular antioxidant capacity caused by long-term oxidative stress and significantly inhibit the accumulation of ROS and MDA. Notably, SRT 2104 demonstrated similar effects in MAC-T cells during lactation. In summary, SIRT1 plays a crucial role in regulating the antioxidant capacity of mammary epithelial cells in dairy cows. This discovery provides valuable insights into the antioxidant mechanisms of mammary cells, which can serve as a theoretical foundation for future mammary health strategies.